37¢ Willow Ptarmigan
Nature of America Series
Issue Date: July 2, 2003
City: Fairbanks, AK
Printed By: Banknote Corporation of America
Printing Method: Lithographed
Perforations: Serpentine Die Cut 10.75 x 10.5 and 10.5 x 10.75
A harsh, treeless plains region, Alaska’s Arctic tundra is the coldest of the nation’s ecosystems. Only hardy mosses, lichens, grasses, and low shrubs grow there.
Covered by snow most of the year, the tundra comes alive in the spring. Birds arrive to nest. A never-setting summer sun warms the air above freezing. Plants grow rapidly and paint the ground with bright flowers. The thawed soil is only inches deep, above a permanently frozen layer that is over 1,000-feet thick in some places.
Mats of lichens shelter nests and runways of small mammals. Caribou, musk oxen, grizzly bears, and small animals graze, and wolves prey on the grazing animals.
In the fall, caribou and most birds migrate south. Only a few birds, like the snowy owl and the raven, stay. Winter temperatures average about -30º F. Small animals burrow in search of shelter and food. Some hibernate; others, like the brown lemming, remain active in snowy tunnels. Furred foot soles and small ears and tails limit heat loss; thick layers of fat provide insulation and energy. The Arctic fox, the snowshoe hare, and ptarmigan grow white coats to match the snow.
The “Arctic Tundra” pane is the fifth in the Nature of America Series. The artwork shows an autumn scene in the Brooks Range in Alaska.